<?php

/**
 * Created by PhpStorm.
 * User: liuweiping
 * Date: 2016/11/30
 * Time: 15:14
 */
class Captcha
{
    private $width;
    private $height;
    private $codeNum;
    private $code;
    private $im;

    function __construct($width = 100, $height = 50, $codeNum = 4)
    {
        $this->width = $width;
        $this->height = $height;
        $this->codeNum = $codeNum;
    }

    function showImg($data = '')
    {
        //创建图片
        $this->createImg();
        //设置验证码
        $this->create_captcha($data);
        //输出图片
        $this->outputImg();
    }

    function getCaptcha()
    {
        $this->createCode();
        return $this->code;
    }

    /**
     * 创建图片
     */
    private function createImg()
    {
        $this->im = imagecreatetruecolor($this->width, $this->height);
        $bgColor = imagecolorallocate($this->im, 255, 189, 181);
        imagefill($this->im, 0, 0, $bgColor);
    }

    /**
     * 设置干扰元素
     */
    private function setDisturb()
    {
        $area = ($this->width * $this->height) / 20;
        $disturbNum = ($area > 250) ? 250 : $area;
        //加入点干扰
//        for ($i = 0; $i < $disturbNum; $i++) {
//            $color = imagecolorallocate($this->im, rand(0, 255), rand(0, 255), rand(0, 255));
//            imagesetpixel($this->im, rand(1, $this->width - 2), rand(1, $this->height - 2), $color);
//        }
        //加入弧线
        for ($i = 0; $i <= 5; $i++) {
            $color = imagecolorallocate($this->im, 255, 255, 255);
            imagearc($this->im, rand(0, $this->width), rand(0, $this->height), rand(30, 300), rand(20, 200), 50, 30, $color);
        }
    }

    private function createCode()
    {
        $str = "23456789ABCDEFGHIJKMNPQRSTUVWXY";
//        $str = "0123456789";

        for ($i = 0; $i < $this->codeNum; $i++) {
            $this->code .= $str{rand(0, strlen($str) - 1)};
        }
    }

    /**
     * 设置验证码
     */
    private function setCaptcha()
    {
        $color = imagecolorallocate($this->im, rand(0, 150), rand(0, 150), rand(0, 150));
        $size = rand(floor($this->height / 5), floor($this->height / 3));
        $x = rand(0, $this->width - $size * $this->codeNum - 5);
        $y = rand($size + 5, $this->height - 5);
//        imagechar($this->im, $size, $x, $y, $this->code{$i}, $color);
        $font = BASEPATH . '/fonts/texb.ttf';
        imagettftext($this->im, $size, 0, $x, $y, $color, $font, $this->code);
    }

    private function outputImg()
    {
        if (imagetypes() & IMG_PNG) {
            header('Content-type:image/png');
            imagepng($this->im);
        } elseif (imagetypes() & IMG_GIF) {
            header('Content-type: image/gif');
            imagegif($this->im);
        } elseif (imagetypes() & IMG_JPEG) {
            header('Content-type: image/jpeg');
            imagejpeg($this->im);
        } else {
            die("Don't support image type!");
        }
        imagedestroy($this->im);
    }

    /**
     * CI自带： Create CAPTCHA
     *
     * @param    array $data data for the CAPTCHA
     * @param    string $img_path path to create the image in
     * @param    string $img_url URL to the CAPTCHA image folder
     * @param    string $font_path server path to font
     */
    private function create_captcha($data = '', $img_path = '', $img_url = '', $font_path = '')
    {
        $defaults = array(
            'word' => '',
            'img_path' => '',
            'img_url' => '',
            'img_width' => '150',
            'img_height' => '30',
            'font_path' => '',
            'expiration' => 7200,
            'word_length' => 8,
            'font_size' => 16,
            'img_id' => '',
            'pool' => '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',
            'colors' => array(
                'background' => array(255, 255, 255),
                'border' => array(153, 102, 102),
                'text' => array(204, 153, 153),
                'grid' => array(255, 182, 182)
            )
        );

        foreach ($defaults as $key => $val) {
            if (!is_array($data) && empty($$key)) {
                $$key = $val;
            } else {
                $$key = isset($data[$key]) ? $data[$key] : $val;
            }
        }
        // -----------------------------------
        // Determine angle and position
        // -----------------------------------
        $length = strlen($word);
        $angle = ($length >= 6) ? mt_rand(-($length - 6), ($length - 6)) : 0;
        $x_axis = mt_rand(6, (360 / $length) - 16);
        $y_axis = ($angle >= 0) ? mt_rand($img_height, $img_width) : mt_rand(6, $img_height);

        // Create image
        // PHP.net recommends imagecreatetruecolor(), but it isn't always available
        $this->im = function_exists('imagecreatetruecolor')
            ? imagecreatetruecolor($img_width, $img_height)
            : imagecreate($img_width, $img_height);

        // -----------------------------------
        //  Assign colors
        // ----------------------------------

        is_array($colors) OR $colors = $defaults['colors'];

        foreach (array_keys($defaults['colors']) as $key) {
            // Check for a possible missing value
            is_array($colors[$key]) OR $colors[$key] = $defaults['colors'][$key];
            $colors[$key] = imagecolorallocate($this->im, $colors[$key][0], $colors[$key][1], $colors[$key][2]);
        }

        // Create the rectangle
        ImageFilledRectangle($this->im, 0, 0, $img_width, $img_height, $colors['background']);

        // -----------------------------------
        //  Create the spiral pattern
        // -----------------------------------
        $theta = 1;
        $thetac = 7;
        $radius = 16;
        $circles = 20;
        $points = 32;

        for ($i = 0, $cp = ($circles * $points) - 1; $i < $cp; $i++) {
            $theta += $thetac;
            $rad = $radius * ($i / $points);
            $x = ($rad * cos($theta)) + $x_axis;
            $y = ($rad * sin($theta)) + $y_axis;
            $theta += $thetac;
            $rad1 = $radius * (($i + 1) / $points);
            $x1 = ($rad1 * cos($theta)) + $x_axis;
            $y1 = ($rad1 * sin($theta)) + $y_axis;
            imageline($this->im, $x, $y, $x1, $y1, $colors['grid']);
            $theta -= $thetac;
        }

        // -----------------------------------
        //  Write the text
        // -----------------------------------

        $use_font = ($font_path !== '' && file_exists($font_path) && function_exists('imagettftext'));
        if ($use_font === FALSE) {
            ($font_size > 5) && $font_size = 5;
            $x = mt_rand(0, $this->img_width / ($length / 3));
//            $x = rand(0, 10);
            $y = 0;
        } else {
            ($font_size > 30) && $font_size = 30;
            $x = mt_rand(0, $img_width / ($length / 1));
//            $x = rand(10, 30);
            $y = $font_size + 2;
        }

        for ($i = 0; $i < $length; $i++) {
            if ($use_font === FALSE) {
                $y = mt_rand(0, $img_height / 2);
                imagestring($this->im, $font_size, $x, $y, $word[$i], $colors['text']);
                $x += ($font_size * 2);
            } else {
                $y = mt_rand($img_height / 2, $img_height - 3);
                imagettftext($this->im, $font_size, $angle, $x, $y, $colors['text'], $font_path, $word[$i]);
                $x += $font_size;
            }
        }

        // Create the border
        imagerectangle($this->im, 0, 0, $img_width - 1, $img_height - 1, $colors['border']);
    }
}